Tracking and navigation systems have been employed in various applications to accurately locate, track and navigate objects in space. In the medical field, tracking systems have been utilized with medical devices to assist surgeons in performing precision surgery.
Typical configurations and methods for tracking objects in an operating room are well known in the art. One such method exploits optical signals (light, radiofrequency, infrared, sound etc.) and optical receivers (photodiodes, CMOS or CCD cameras) to locate the position and orientation of medical devices relative to a patient's anatomy. Optical tracking systems are commonly used due to their accuracy and adaptability.
The optical tracking systems generally comprise the following. Three or more active or passive markers that emit or reflect optical signals are arranged in a known geometry on a tracking array. Two or more optical receivers are housed away from the patient in the operating room to receive signals emitted or reflected from the markers. A processing unit electrically connected to the optical receivers analyzes the incoming signals to calculate the position and orientation of the tracking array.
The tracking arrays are fixed to both a patient's anatomy and to the medical device. Using techniques well known in the art, the coordinate frames of the optical sensors, the tracking arrays, the patient's anatomy, and medical device can be calculated relative to each other. During surgery, the markers periodically emit or reflect signals that are captured by the optical sensors and processed to calculate the position and orientation of the medical device relative to the patient's anatomy of interest.
The tracking system described has been exploited for various medical applications. For example, the marker arrays have been attached to hand-held devices such as the ES2 Spinal System manufactured by Stryker. The surgeon can visualize pedicle screw placement relative to a patients vertebrae on a display monitor in the OR. Another application is to use the tracking system with a semi-active computer assisted device such as the RIO Robotic Arm Interactive Orthopedic System manufactured by Mako that provides visual feedback as to the position and orientation of a reamer during acetabular preparation in total hip arthroplasty. Similarly, the tracking system can be used with fully active computer assisted devices to provide location information that is sent to a control unit that guides movement of the device relative to a patient's anatomy.
Currently, the emitted or reflected signals from the markers merely provide a means to accurately detect the markers location in space and discern the marker from the background (signal to noise). However, there have been recent advancements in light emitting diode (LED) technology that provide a means to transmit data at higher rates than previously feasible that can serve a plurality of valuable uses especially in a medical setting.
Recently, data rates over 1.6 Gbit/s have been demonstrated using visible light emitted from LEDs and optical sensors like CCD or CMOS cameras. With the small size of the components needed, and ability to send signals long distances through electrical connections, several new applications arise every day for this technology. For example, LEDs can now be placed in various locations of a home, shopping center, department store or office work place to transmit data to computers, cell phones, fax machines, etc. The streamed data could connect users to the Internet, send advertisements, provide location information etc.
Additionally, there are many advantages to using visible light to transmit data in contrast to traditional radio frequency. Radio waves can cause electromagnetic interference with surrounding electronic equipment and can penetrate walls, which is a potential security risk. Light, however, is confined to line of sight, poses no risk of electromagnetic interference and has approximately 10,000 times more bandwidth available compared to radio waves.
Considering traditional optical tracking systems already include LED markers and optical sensors, the systems can be altered to transmit tracking and additional information at theoretical rates in excess of 500 Mb/second to serve a plurality of functions. Unfortunately, the complexities of the surgical setting and high tolerances associated with surgery have prevented LED data transmission in the surgical setting.
Thus, there exists a need for a light based data transmission system. There further exists a need for such a system in the context of robotic surgery.